Testicular and plasma ascorbic acid levels in mice following dietary intake: a high-performance liquid...

A modified buffer system is reported for the analysis of vitamin C in mouse plasma and testes, on a reversed-phase high-performance liquid chromatographic column with ultraviolet detection. The buffer, consisting of 0.1 M NaH2PO4 and 0.2 mM Na2EDTA adjusted to pH 3.1 with orthophosphoric acid, resolved the ascorbic acid (AA) peak allowing clear quantitation of the chemical. The method is also applicable to the assay of dehydroascorbic acid after its reduction to ascorbic acid, and overcomes problems of AA stability encountered in previously reported procedures. Using the present technique, variations in the vitamin levels of plasma and testes are studied from 3 to 29 days after the commencement of feeding a vitamin C-rich diet (1%, w/w) in mice. The plasma AA levels were elevated above the controls by a factor of 2.5 by day 8. Contrary to this, testicular AA levels increased marginally (1.2-fold) by day 12 and were maintained at levels close to the control values thereafter. It appears that the feedback inhibition mechanism which is effective in plasma is not operational in the testes. The findings are of clinical significance in that testicular AA levels do not change significantly as a result of dietary intake of vitamin C, whereas plasma AA levels do show an increase.